Main switch with and without housing

Master switches serve as a central switching point to completely switch off the entire current flow in an electrical system for maintenance, repair or emergency work. When the main switch is switched off switch, all circuits and devices connected to the electrical system are de-energized. switched off. The main switch is therefore an elementary component of the electrical system. The exact characteristics and specifications of a main switch can vary depending on the application and the specific requirements, such as the external environment. Therefore, when selecting and installing the right main switch the safety regulations and standards [anchor link to safety regulations] must be observed.

Main switch with and without housing

At Hilpress, we distinguish between main switches with and without an enclosure. The main difference in these switches is the physical cover or protection provided by the enclosure. In addition the switches differ in the way they are used.

Main switch with housing

Master switches with enclosure are normally installed in a closed housing or a switch cabinet installed. The enclosure offers the main switch and the surrounding electronics additional protection against external external influences such as dust, moisture or mechanical damage. It also provides protection against accidental contact or unauthorized access to the main switch. The housing can also contribute to sound insulation to reduce noise that can occur when the main switch is operated.

Main switch without housing

Main switches without an enclosure are installed additional protective cover directly into an electrical system or a distribution board. As it has no housing, it is more susceptible to dirt, moisture or damage. damage. The access to the main switch without a housing can be a practical solution in certain situations, but it also but also a higher risk.

Application areas of main switches

Main switches are primarily used in electrical installations to switch the power supply on or off.

Switchgear and distribution cabinets

Main switches are used as main disconnectors in switchgear and distribution cabinets. This allows the entire current flow in the system can be interrupted and individual circuits or devices can be switched off without the entire system being from the having to be disconnected from the mains.

Industrial facilities

Main switches are used in industrial plants, factories or production facilities to ensure the power supply to large machines, systems and production lines. This enables maintenance work, repairs or the guarantee work safety.

What are the most important regulations for main switches

• Only the ON and OFF switch must be present.
• In addition, the OFF switch must be lockable.
• The TRIPPED circuit is not considered an additional switching position and is permissible.
• However, the isolating properties must already be guaranteed in the TRIPPED position with the main contacts open..
• The main switch does not have to be closed in the TRIPPED position.

What safety regulations and standards apply to main switches?

Safety regulations and standards vary from country to country and region to region. Therefore is it is advisable to familiarize yourself with the safety regulations and standards applicable at the place of use. There are however standards that are widely used internationally and are regarded as a reference in many countries:

• IEC 60947 (International Electrotechnical Commission): International standard for low-voltage switchgear and controlgear
• IEC 60947-3: Detailed requirements for main switches within IEC 60947
• DIN EN 60947: European standard for main switches, based on IEC 60947
• VDE standards: Contain norms and safety standards for electrical safety. All main switches installed in Germany main switches installed in Germany must also comply with this standard

In the USA, the standards and safety regulations are regulated in the following documents:

• UL 508 (Underwriters Laboratories): Defines safety requirements for industrial control circuits and switching devices, this also includes main switches
• NEC (National Electrical Code): Requirements and regulations for electrical installation, all in the USA installed main switches must comply with this standard
• NFPA 70 (National Fire Protection Association): Contains detailed requirements and regulations for electrical installations